Controlling of apoptosis and proliferation of HepG2 cancer cells by treatment of plasma jet and N-acetylcysteine combination

It is well known that atmospheric pressure plasma could induce apoptosis of cancer cells. [1][2] However, the interaction and mechanism between plasma and cancer cells has not been fully understood yet. [3] Here, we report the controlment of apoptosis and proliferation of human hepatocellular carcinoma cell (HepG2) by combined treatment of He/O₂ plasma jet and N-acetylcysteine (NAC, free radical scavenger). It is found that the fate of HepG2 cells could be controlled by plasma treatment time together with NAC pretreatment. Pure plasma treatment could induce apoptosis of HepG2 cells. However, on one hand, 15s plasma with NAC pre-treatment could enhance proliferation of HepG2 cell as a function of NAC concentration. On the other hand, NAC-pretreatment could markedly compromise apoptosis effect by long time plasma treatment (e.g. >240s) without proliferation observed. The NAC and 15s plasma treatment accelerates the G1 to S phase transition of HepG2 cells causing proliferation while long time plasma treatment arrests the cell cycle at the G2/M phase inducing apoptosis.